1. Field of the Invention
The present invention relates to a probe card, which is used to perform a conduction test on a semiconductor device or other substrates, and to a substrate for manufacturing the substrate.
2. Description of the Related Art
A wafer test is normally performed when fabricating a semiconductor device. A probe card having a plurality of probe pins is used in the wafer test. A semiconductor having a plurality of pads is formed on the wafer substrate. The probe pins are each connected to an associated one of the pads. Various characteristics of the semiconductor device are measured in accordance with a predetermined conduction test program. A variety of probe cards having different configurations are known in the art, such as a cantilever type probe card and a patterning type probe card.
Recent semiconductors, such as LSIs, have higher integration, smaller pitches, and higher frequencies. Accordingly, there is a demand for LSI testing probe cards to have higher integration, smaller pitches, and higher frequencies.
FIG. 1 shows a contact probe 41 used in a patterning type probe card that answers such demand. The contact probe 41 includes an insulation plate 42, which is made of polyimide resin. A plurality of wires 43 are formed on the insulation plate 42 by performing lithography.
The width of each wire 43 continuously changes between the upper end where the width is relatively wide and the lower end where the width is relatively narrow. The lower end of the wire 43 functions as a contact 44, which extends downward from the insulation plate 42. The contact 44 is engaged with a pad of an LSI. The wires 43 are formed through a technique that requires the same accuracy as the wire printing technique performed when fabricating the LSI. Accordingly, the pitch of the contacts 44 in the contact probe 41, which is smaller than the pitch of probe pins in a cantilever type probe card, is optimal for performing conduction test an a highly integrated LSI.
Electric noises affect the conduction test and evaluation of the test result in an undesirable manner. To prevent noise, the contact probe 41 has through holes 45, which extend through the wide upper ends of predetermined wires 43 (at positions relatively separated from the contacts 44). The through holes 45 are used to connect the corresponding wires 43 to a ground layer (not shown). These wires 43 connect predetermined pads to the ground layer to avoids undesirable noise influence.
The contact probe 41 of FIG. 1 is connected to a plurality of pads, which are arranged along the four sides of an LSI chip, to test the LSI chip. A probe card has four of the probe cards 41 shown in FIG. 1 in correspondence with the four side of the LSI chip.
The probe card is manufactured in the following manner. First, as shown in FIG. 2, the wires 43 of the four contact probes are formed on an insulation film 47. Each contact probe 41 is formed by cutting the insulation in a trapezoidal manner.
The number of pads and the location of the pads connected to the ground differ between LSI types. Thus, the probe card must be changed in accordance with the LSI type. That is, in accordance with the LSI chip type, the number of wires formed on the insulation film 47 and the position of through holes must be must be changed in accordance with the type of LSI chip. Thus, the patterning type probe card is difficult to mass-produce and more expensive to produce in comparison to other types of probe cards.
As the number of times the contact probe 41 contacts the LSI pads increases, physical damage, such as breakage, may be inflicted on the contacts 44 thereby deteriorating the contact probe 41. When only one of the contacts 44 is damaged, it would be difficult to repair only the damaged contact 44. Thus, the whole contact probe 41 must be replaced.
As shown in FIG. 2, the wires of the four contact probes 41 are formed on the single insulation film 47. Thus, when one of the contact probes 41 is damaged, the damaged contact probe 41 is either repaired on replaced. However, the remaining three contact probes 41 cannot be used during this period. Accordingly, the cost for repairing the prior art probe card is high.